Stable, active CO2 reduction to formate via redox-modulated stabilization of active sites

Le Li; Adnan Ozden; Shuyi Guo; F Pelayo Garcı A de Arquer; Chuanhao Wang; Mingzhe Zhang; Jin Zhang; Haoyang Jiang; Wei Wang; Hao Dong; David Sinton; Edward H Sargent; Miao Zhong

doi:10.1038/s41467-021-25573-9

Stable, active CO₂ reduction to formate via redox-modulated stabilization of active sites

Nat Commun. 2021 Sep 1;12(1):5223. doi: 10.1038/s41467-021-25573-9.

Authors

Le Li^#¹, Adnan Ozden^#², Shuyi Guo³, F Pelayo Garcı A de Arquer⁴, Chuanhao Wang¹, Mingzhe Zhang¹, Jin Zhang¹, Haoyang Jiang¹, Wei Wang³, Hao Dong⁵, David Sinton², Edward H Sargent⁶, Miao Zhong⁷

Affiliations

¹ College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructure, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, China.
² Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
³ Kuang Yaming Honors School & Institute for Brain Sciences, Nanjing University, Nanjing, China.
⁴ Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
⁵ Kuang Yaming Honors School & Institute for Brain Sciences, Nanjing University, Nanjing, China. donghao@nju.edu.cn.
⁶ Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada. ted.sargent@utoronto.ca.
⁷ College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructure, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, China. miaozhong@nju.edu.cn.

^# Contributed equally.

Abstract

Electrochemical reduction of CO₂ (CO₂R) to formic acid upgrades waste CO₂; however, up to now, chemical and structural changes to the electrocatalyst have often led to the deterioration of performance over time. Here, we find that alloying p-block elements with differing electronegativities modulates the redox potential of active sites and stabilizes them throughout extended CO₂R operation. Active Sn-Bi/SnO₂ surfaces formed in situ on homogeneously alloyed Bi_0.1Sn crystals stabilize the CO₂R-to-formate pathway over 2400 h (100 days) of continuous operation at a current density of 100 mA cm^-2. This performance is accompanied by a Faradaic efficiency of 95% and an overpotential of ~ -0.65 V. Operating experimental studies as well as computational investigations show that the stabilized active sites offer near-optimal binding energy to the key formate intermediate *OCHO. Using a cation-exchange membrane electrode assembly device, we demonstrate the stable production of concentrated HCOO^- solution (3.4 molar, 15 wt%) over 100 h.